The present invention relates generally to a data entry systems and, more particularly, to a data entry system based on a limited number of input keys.
For many years, 12-key keypads (FIG. 1) have been used in a variety of applications. In fact, such keypads have been made ubiquitous through their availability and implementation in devices as far ranging as automatic teller machines (ATMs) to point of sales (POS) terminals. In fact, as technology has progress, ATMs have reached a degree of functionality that they are used in a multitude of ways other than for dispensing money.
Even more commonly, 12-key keypads have been fixtures of touch-tones telephones from their very inception. Naturally, the same keypads are used in telephones of all kinds, including cordless and cellular telephones. More recently, as cellular phones have increased in popularity, they have also become more multifunctional. These devices are now called upon to perform functions traditionally associated with Personal Digital Assistants (PDAs), including the ability of the user to enter data or text for storage or for sending as a message. Instant messaging, which requires interactive communication with others, has exploded in popularity as a cell phone application. The ability to enter data quickly and easily is a very important aspect of usability of these devices.
Text or data entry systems, as described above, are typically implemented in at least two different ways. In one method, a multiple tap system is a way of using the conventional keypad of a telephone to write text. The multi-tap method requires the user to press the ‘2’ through ‘9’ keys for writing letters, the ‘1’ and ‘0’ keys for entering symbols and punctuation, and, optionally, the ‘*’ and ‘#’ keys for moving the cursor to the left and right.
For any of the alphabet letters, the user is required to press the 2 through 9 keys to scroll through the letters and number choices associated with that key. For example, the 2 key on most telephones and cellular phones have printed on them the letters ‘a’, ‘b’ and ‘c’. When the 2 key is pressed once, the character ‘a’ is displayed. The second press of the same key displays the character ‘b’, the third press of the key displays the character ‘c’ and the fourth press of the key displays the number ‘2’. Subsequent key presses of the ‘2’ key recycle the above sequence. The other keys work in a similar manner.
In another type of text entry system, pressing a number indicates the particular bank of letters being selected. For example, pressing 2 selects the bank of letters ‘ABC’. Then pressing 1, 2 or 3 indicates whether A, B or C is to be entered. To effect a change in case of the letter, additional key presses are required.
In still other systems, such as those available from Tegic Communications, Inc. and Motorola, Inc., predictive text entry systems based upon dictionary lookups are provided. In such systems, words or even entire sentences may be predicted. A user presses the numbers associated with the letters of a word and an internal database is scanned to determine the intended word.
Each of the above systems has its own disadvantages. In the multi-tap method, an inordinately large number of key presses are required to create a word. For example, the word ‘call’ requires ten key presses. In the predictive text entry systems, the user must look down at the screen to ensure that the proper word or sentence has been predicted correctly. If not, manual intervention is required to select the correct choice from among several. Unfortunately, this can be cumbersome and distracting since the user must look at the screen and make corrections through additional key presses.